First generation infrared (IR) guided missiles could possibly be avoided by pilot manoeuvres that consisted of pointing a targeted aircraft in the direction of the sun to blind the IR missile's detector system or by launching decoy flares onto which the missiles detector would lock and decoy the missile away from the aircraft. Current decoy flares are generally of the pyrotechnic type which produces radiation by combustion of solid pyrotechnic compositions. The most commonly used composition, named MTV composition, is composed of magnesium, teflon and Viton*. This MTV composition produces a very hot flame and provides an intense point source of IR radiation that should attract this first generation of IR guided missiles. However, advances in missile IR seekers have significantly reduced the effectiveness of currently fielded pyrotechnic flares. None of the known systems offers the required protection performance against these newer missiles. FNT * Trade Mark
The new generation of IR guided missiles are equipped with one or more electronic counter-countermeasures that can discriminate and reject aircraft protective countermeasures such as the current decoy flares. These new IR guided missiles have detection systems that can usually distinguish and analyze three bands in the spectral emissions of aircrafts. Therefore, any detected signal in which the band intensities and ratios do not conform to the target aircraft's spectral signature would be recognized as a countermeasure and ignored. Countermeasure flares would now have to produce a spectral signature similar to those of aircrafts in order to be effective. This is not the case with pyrotechnic flares. Pyrotechnic flare's spectral signature are, in fact, very different from that of an aircraft because they emit principally in the first spectral band that would be analyzed by newer guided missiles IR seeker whereas a jet aircraft's signature shows high intensities in the second and third bands. This spectral mismatched signature generally limits the usefulness of current pyrotechnic flares to the previous generation of IR guided missiles.
Operational analysis, based on measured experimental flare performance, show that pyrophoric flares offer a strong potential to provide the required performance to decoy the newer generation of IR seeking missiles. The spectral signature of a pyrophoric liquid, such as alkyl aluminum compounds that burn spontaneously when sprayed into the air, more closely resemble a jet aircraft's spectral signature so that an IR seeking missile would not recognize that type of flare as a countermeasure. Some attempts were made by others to develop effective flares using pyrophoric liquids during the 1980's but were unsuccessful.
The basic functioning principles of any pyrophoric flare would have very little in common to the existing pyrotechnic flare except for the fact that they are both ejected from a launcher by an impulse cartridge. A pyrophoric flare would require a liquid in a perfectly sealed reservoir since pyrophoric liquids react and burn on exposure to air using the oxygen of the air as an oxidant. Pyrotechnic flares, on the other hand, use a solid grain composition contained in a protective shell. Some means would be required in a pyrophoric flare to eject the pyrophoric liquid through a calibrated nozzle such as a gas generator to provide a certain pressure profile inside the flare to break rupturing discs and eject the liquid. Therefore, a high stress resistance container and special sealing component attachments would be required for a pyrophoric flare. These items are not required for a pyrotechnic flare. In addition, mobile and/or removable components of the ignition system for any pyrophoric flare would require special sealing devices to prevent any pressure leaks through the ignition system during the whole functioning of the flare. This is not a concern for a pyrotechnic flare. Furthermore, pyrophoric liquids, such as alkyl aluminum compounds, are incompatible with many materials and especially with most polymers. These constraints require a completely new flare design for pyrophoric flares which has not existed up to present.